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Questions and Answers
What is the average value for the Anterior Ratio?
What is the average value for the Anterior Ratio?
If the Bolton ratio is high in the upper jaw and there is Angle Class I closure in the first molars, but no overjet in the anterior region, what is likely to occur?
If the Bolton ratio is high in the upper jaw and there is Angle Class I closure in the first molars, but no overjet in the anterior region, what is likely to occur?
What happens if the tooth size discrepancy is less than 1.5 mm?
What happens if the tooth size discrepancy is less than 1.5 mm?
What is the average value for the Overall Ratio?
What is the average value for the Overall Ratio?
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If the Bolton ratio is high in the lower jaw and there is Angle Class I closure in the first molars, what is likely to occur?
If the Bolton ratio is high in the lower jaw and there is Angle Class I closure in the first molars, what is likely to occur?
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What happens if the tooth size discrepancy is larger than 1.5 mm?
What happens if the tooth size discrepancy is larger than 1.5 mm?
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What type of malocclusion is characterized by the presence of diastemas in the upper tooth arch?
What type of malocclusion is characterized by the presence of diastemas in the upper tooth arch?
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In the Hays-Nance space analysis method, what does the 'Required Arch Length' represent?
In the Hays-Nance space analysis method, what does the 'Required Arch Length' represent?
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Which of the following is a characteristic of Angle Class I malocclusion with normal overjet?
Which of the following is a characteristic of Angle Class I malocclusion with normal overjet?
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In the Hays-Nance space analysis method, how is the 'Available Arch Length' calculated?
In the Hays-Nance space analysis method, how is the 'Available Arch Length' calculated?
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Which of the following malocclusions is characterized by a shift in the molar bite to Angle Class II?
Which of the following malocclusions is characterized by a shift in the molar bite to Angle Class II?
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Which of the following is a characteristic of Angle Class I malocclusion with normal overjet and no crowding in the lower arch?
Which of the following is a characteristic of Angle Class I malocclusion with normal overjet and no crowding in the lower arch?
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What does a negative arch length deviation indicate?
What does a negative arch length deviation indicate?
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Which method is preferred for measuring tooth dimension in mixed dentition according to the text?
Which method is preferred for measuring tooth dimension in mixed dentition according to the text?
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Who proposed the formula for determining the magnification of radiographs in space analysis?
Who proposed the formula for determining the magnification of radiographs in space analysis?
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What is the purpose of Moyers estimation tables?
What is the purpose of Moyers estimation tables?
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In space analysis, what does a positive arch length deviation indicate?
In space analysis, what does a positive arch length deviation indicate?
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Which method is NOT recommended for calculating the mesiodistal dimension of unerupted permanent teeth?
Which method is NOT recommended for calculating the mesiodistal dimension of unerupted permanent teeth?
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Study Notes
Anterior Ratio and Overall Ratio
- Anterior Ratio is calculated by dividing the sum of mesiodistal width of mandibular anterior teeth (3-3) by the sum of mesiodistal width of maxillary anterior teeth (3-3) and multiplying by 100.
- Average value of Anterior Ratio is 77.2 (range: 75.55-78.85).
- Overall Ratio is calculated by dividing the sum of mesiodistal widths of 12 mandibular teeth (6-6) by the sum of mesiodistal widths of 12 maxillary teeth (6-6) and multiplying by 100.
- Average value of Overall Ratio is 91.3 (range: 89.39-93.21).
Tooth Dimension Discrepancy
- Tooth dimension discrepancy is calculated by comparing the values found according to the formulas with the values in Bolton's standard table.
- If the tooth size discrepancy is less than 1.5 mm, it is insignificant.
- Larger values create treatment problems.
Consequences of Bolton Ratio
- If the Bolton ratio is high in the upper jaw:
- With Angle Class I closure in the first molars, an overjet will occur in the anterior region.
- With Angle Class I closure in the first molars and no overjet, crowding will occur in the upper teeth.
- With Angle Class I closure in the first molars and no overjet and crowding, diastema will occur in the lower tooth arch.
- With no diastema in the lower arch, no crowding in the upper arch, and normal overjet, the posterior bite will shift to Angle Class III.
- If the Bolton ratio is high in the lower jaw:
- With Angle Class I closure in the first molars, head-to-head or crossbite will occur in the lower anterior region.
Arch Length Deviation
- Arch Length Deviation (ALD) = Available arch length - Required arch length.
- If ALD is negative, space is needed in the arch (crowding).
- If ALD is positive, there is excess space in the arch (diastema).
Space Analysis in Mixed Dentition
- Three approaches to calculate the mesiodistal dimension of unerupted permanent teeth:
- Measuring tooth dimension on radiographs.
- Estimation from Proportion Tables.
- Other methods (not specified).
Measurement on Radiographs
- Measure tooth width on periapical X-ray film.
- Magnification ratio is calculated by comparing the mesiodistal size of a tooth in the model and in the X-ray.
Estimation from Proportion Tables
- Tables are used to estimate the mesiodistal dimensions of unerupted canines and premolars based on the sum of the mesiodistal widths of the lower incisors (incisor amount).
Hays-Nance Analysis Method
- Required Arch Length is calculated by measuring and summing the mesiodistal width of each permanent tooth mesial to the first permanent molars.
- Available Arch Length is calculated by two methods: yellow wire method and measurement with a Boley caliper.
- Dental arch is divided into four segments for measurement.
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Description
Test your knowledge on dental malocclusion types including Angle Class I, overjet, crowding, diastemas, and molar bite shifts. Learn about the relationship between these factors in orthodontics.
